Refrigerating system



July 18, 1939.

w. E. WHITNEY REFRIGERATING SYSTEM Filed Oct. 27, 1937 Ina/672507 lk zzkkzrrali xwwf/wu Patented July 18, .1939

PATENT "OFFICE REFRIGERATING SYSTEM William E. Whitney, Cambridge, Mass,assignor, by mesne assignments, to Stator Corporation, a corporation ofRhode Island Application October 27, 1937, Serial No. 171,301

7 Claims.

This invention relates to an improved refrigerating apparatus of thegeneral type disclosed in United'States Patent No. 1,761,551 to EastmanA. Weaver, and in the copending applications of Lyman F. Whitney, SerialNos. 171,325 and'171,- 324, filed on 'even date herewith.

As taught in the first-identified application, systems of thischaracter,particularly when em-' ploying an aqueous refrigerant with an anti- ]0freeze agent, sometimes are characterized by a tendency to developsludge, such a sludge consisting of mercury particles and liquidrefrigerant and having varying characteristics quite closely resemblingthe characteristics of muds of different consistencies. Such a sludgeordinarily collects in the cooler and, in many cases, apparently may 'bedue to some interaction of refrigerant and mercury particles which passinto the condenser and which return from thethat this effect maybesubstantially enhanced if the hot pipe is arranged so that the vapormust follow a somewhat tortuous course. The pipe, for example, may beprovided wtih a plurality of internal fins against which the vaporpassing from the aspirator to the condenser may strike. Such fins affectthe refrigerant vapor stream and the included stray mercury particles insuch a manner that the mercury tends to settle out of the refrigerantupon condensation, and.thus return to the trap means in the lower partof the system, rather than being suspended in the refrigerant to formsludge which passesinto the body of'liquid refrigerant in the cooler.

In the accompanying drawing:

Fig. 1 is a diagrammatic view of a refrigerating system in which thepresent invention is incorporated; and

Fig. 2 is a broken isometric; view of a portion of the pipe extendingbetween the aspirator and the condenser showing the arrangement of thefins in the same in accordance with this invention, the position of thisportion of the pipe being indicated by line 22 of Fig. 1.

The present invention may 1e employed in a refrigerating system of thegeneral type disclosed in the above-identified Weaver patent, whichischaracterized by a propellant circuit through which a heavy propellantcirculates to pump refrigerant vapor through a refrigerant circuit, thecircuits having a part in common where the refrigerant vapor isentrained in a stream of the propellant vapor, and where the propellantvapor may be condensed.

Such'a system is provided wth a boiler l, which may contain a body ofliquid mercury and which is connected by a riser pipe 2 to an aspiratornozzle 3, the latter being arranged to emit mercury vapor at highvelocity into a mixing chamber 4, which receives refrigerant vapor fromthe cooler 6 through a vapor duct 5. The mixed vapors pass into a funnelI, where the refrigerant is compressed and where propellant iscondensed. Condensed propellant passes from the funnel into a drain. 8,while the refrigerant vapor passes through a duct 9 to the refrigerantcondenser Ill.

The refrigerant condenser is arranged so that condensate may flow into achamber ll provided with an outlet drain 12. The chamber II is alsoconnected to a gas-receiving duct l3, which is arranged to supplynon-condensable gases to a purger ll, of the type fully disclosed in thecopending application of Lyman F. Whitney, Se- .rial No. 167,402 filedOctober 5, 1937. This purger includes a drop tube l5 of restricteddiameter, which receives condensed mercury in the form of separate dropsor globules. The mercury globules fall through this tube and compressthe gases which are exhausted to the atmosphere through a'mercury body16 arranged in ,a vat I! at the lower part of the purger. The mercuryrises in a return duct 23 disposed about the drop tube l5, and isreceived fromthe'latter by a pipe 25 containing a pressure balancingcolumn of the mercury and serving as a boiler return pipe.

The lower part of the drain 8 may be connected to two upwardly extendingpipes, one 'pipe 21 being connected to the upper part of the purger tosupply mercury to the same, and the other pipe 28 inclining upwardly .toa connection with the refrigerant return pipe l2, which extendsdownwardly from the refrigerant condenser. The inclined pipe 28 extendsabove this connection and is provided with an upwardly extendingcontinuation 26, the upper part of which is above the level of theliquid refrigerant in the cooler 6, and. is connected to a downwardlyextending pipe section 3|]. The lower part of the latter has aconnection with a duct 3|, which isin turn connected to the lower partof .cooler E. Duct 3| forms one leg of a trap 33, the opposite leg ofwhich is connected to a drain 34 receiving mercury, which condenses inthe mixing chamber 4. This leg of the trap is also provided with aspill-over connection with a pipe 31, the lower part of which providesone leg of a trap 38, the opposite leg of which is connected to themercury return pipe 25. When mercury fills the trap 33 to the level withits connection to the pipe 31, the mercury spills over into this pipe.Thus the connection between pipes ill and II normally contains a body ofliquid which tends to have about the same level as this spill-overconnection.

The level of the mercury in the trap assembly at the lower end of thereturn pipe i2, is determined by the height 'of the spill-overconnection between the purger and pipe 21, the mercury tending to standat this level in this trapassembly, as indicated by the dot and dashline of Fig. 1, when the system is not in operation. During operation ofthe system, however, the pressure in the cooler is lower than thepressure in the condenser, and a pressure-balancing column of liquid inthe pipe 26 stands above the level indicated by the dot and dash line tobalance this pressure difference.

Condensed refrigerant in pipe I! tends to depress themercury in thelower part of this pipe, piling up so that it passes through the trapprovided by the lower part of pipe 12 and by pipe 26, thus risingthrough the latter and spilling over into the pipe 30. The refrigerantcollecting in the latter depresses the mercury in the trap provided bythe lower part thereof and by the pipe II, thus rising through the pipe31 to the cooler. Such a trap arrangement and the action of the sameunder difierent operating conditions, is more fully disclosed, andclaimed in the copending application of Lyman F. Whitney, Serial No.171,325.

As explained in that above-identified application, a systemof thischaracter may employ an aqueous refrigerant with an anti-freeze agent,which tends to depress the freezing point of the refrigerant below thefreezing pointof water, so

that a low temperature may be obtained in the cooler. Under someoperating conditions, particularly when an anti-freeze agent is employedin the aqueous refrigerant, sludge may tend to collect in the cooler.-This sludge apparently may be caused by the interaction of the mercuryand refrigerant which passes into the refrigerant condenser as taught inthe above-identified application Serial No. 171,325. The fiowof mercuryto the condenser and the development of sludge in this manner arematerially impeded, if the vapor pipe extending from the aspirator tothe condenser is heated. Thus such a pipe may, for example, be disposedadjoining one of the hot aspirator funnels or adjoining the stack whichreceives exhaust gases from the burner associated with the boiler I, or,if desired, the pipe may be juxtaposed to the 'mercur'y riser pipeextending from the boiler to the aspirator, as disclosed in copendingapplication Serial No. 171,324;

I have discovered that the effectiveness of such a pipe in preventingsludge formation may be materially increased if the warm portion of thepipe is provided with internal fins against which the vapor streamstrikes as it flows to the cooler. As explained in the copendingapplication of ,Lyman F. Whitney, Serial No. 171,324, filed on 'may losetheir charges so that they may thereafter coalesce into liquid mercuryin the normal manner. Of course, the fins provided by the presentinvention afford additional warm surfaces di-' rectly in the paths ofthe particles and thus may materially aid in removing the electricalcharges therefrom. 7

As shown more particularly in Fig. 2, the pipe 9 may be provided with aplurality of fins El, each of which occupies at least one-half theinternal cross-sectional area ofthe pipe, but preferably has a somewhatgreater area, these fins being staggered upon alternate sides of the;pipe, as shown in Fig. 2, and as indicated by' the dotted lines inFig. 1. Thus the vapors passing from the aspirator funnel I to thecondenser l0 strike these fins and, rather than flowing directly throughthe duct, must pass about the edges of successive staggered fins in asomewhat tortuous course. In order to prevent the pocketing of condensedvapor between the fins, small openings i may be provided in the fins onthe lower side of the pipe to permit liquid condensate to drain back tothe lower part of the system. a

For purposes of illustration, a portion of the pipe 9 adjoining thefunnel .I is shown as provided with fins. In the illustrated example ofthis invention, the funnel is shown provided with a plurality of coolingfins 46, from which the heat is radiated to the pipe 9. Also, asillustrated herein, the upper part of the pipe 9 may also be juxtaposedto the stack 41, which extends upwardly from the burner, which isassociated with the boiler I. Inorder to facilitate the heating of thepipe 9, a plate or strip 48 may be welded to the stack and arranged inclose juxtaposition to the upper part of the pipe 9. It is to beunderstood, however, that the principles of this invention may beemployed, if desired, when the pipe 9 is arranged to receive heatradiated from the riser pipe which extends from the boiler to theaspirator, such an arrangement of the pipe being shown in the copendingapplication Serial No.

In practice, an arrangement of the type disclosed herein-has been foundparticularly advantageous when the anti-freeze agent isin the form ofthe monomethyl ether of ethylene glycol, or the latter and a relativelysmall amount 'of ethylene diamine. Thus, for example, the refrigerantmay comprise 70% by weight of water and 30% by weight'of the monomethylether of ethylene glycol, or 70% by weight of water, 25% or more byweight of the monomethyl ether of ethylene glycol, and or less by weightof ethylene diamine. I

It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modificationsand equivalents which fall within the scope of the appended claims.

1. Refrigerating apparatus of the class described comprisinga'propell'ant circuit and a refrigerant circuit including a condenserand a cooler, said circuits having a part in common where a stream ofpropellant vapor pumps refrigerant vapor from the cooler to thecondenser,

said part being provided with cooling means tosaid part being providedwith coolingmeans to cause the condensation of propellant, therefrigerant circuit including a duct extending from said part to thecondenser, said duct being in heat transfer relation to a warm part ofthe system and being provided with a plurality of inwardly projectingfins against which the vapors must strike in flowing through the pipe.

3. Refrigerating apparatus of the class described comprising apropellant circuit and a relrigerant circuit including a condenser and acooler, said circuits having a part in common where a stream ofpropellant vapor pumps refrigerant vapor from the cooler to thecondenser, said part being provided with cooling mea'ns to causecondensation of propellant, the refrigerant circuit including a ductextending from said part to the condenser, said duct being in heattransfer relation to a warm part of the system and having a plurality ofinwardly directed, oppositely disposed, staggered fins.

4. Refrigerating apparatus of the class described comprising apropellant circuit and a refrigerant circuit including a condenser and acooler, said circuits having a part in common where a stream ofpropellant vapor pumps refrigerant vapor from the cooler to thecondenser, said part being provided withcooling means to causecondensation of propellant, the refrigerant circuit including a pipeextending from said part to the condenser, said pipe being in heattransfer relation to a warm part of the system and having a plurality ofinwardly directed, oppositely disposed, staggered fins, the fins in thelower part of the pipe being provided with openings to permit thedrainage of condensate away from the condenser.

5. Refrigerating apparatus of the class described comprising apropellant circuit and a refrigerant circuit including a condenser and acooler, said circuits having a part in common where a stream ofpropellant vapor pumps refrigerant vapor from the cooler to thecondenser, said propellant circuit containing a body of liquidpropellant in the form of mercury, said cooler containing a body ofaqueous refrigerant, the refrigerant circuit including a duct betweensaid common part and the condenser, said duct being in heat transferrelation to a warm part of the system and being arranged to cause thevapor flowing through this duct to follow a tortuous course, whereby theformation of sludge is impeded.

6. Refrigerating apparatus of the class described comprising apropellant circuit and a refrigerant circuit including a condenser and acooler, said circuits having a part in common where a stream-ofpropellant vapor pumps refrigerant vapor from the cooler to thecondenser, said part being provided with cooling means to cause thecondensation of propellant, the refrigerant circuit including a ductextending from said part to the condenser, said duct having a pluralityof internal protuberances projecting into the path of the vapor passingto the condenser.

7. Method of refrigeration comprising entraining refrigerant vapor froma region of refrigeration in a stream of mercury vapor, condensing themajor portion of the mercury out of the resulting stream of mixedvapors, directing the remaining vapor in a stream against a plurality ofwarm surfaces directly in its path thereby to cause coalescing ofmercury particles, then condensing the vapor and directing thecondensate back to the region of refrigeration.

